Breaching walls, including reinforced concrete walls, are often required during military operations to allow soldiers and equipment to pass through a breach in the wall. Current technology includes the use of closely-spaced multiple shots of 105 mm M393A2 High Explosive Plastic rounds fired from a Mobile Gun System to create a sufficiently sized breach. This is a difficult procedure under ideal conditions, much less while under fire.
A problem with conventional wall-breaching systems is that the concrete is often removed only to leave a re-bar skeleton in the breach. The re-bar must then be cut and removed to permit passage of troops. Some breaching devices have a re-bar removal feature. For example, an Explosively Formed Projectile that forms a ring-shaped projectile (donut) can be used to cut the re-bar; however, this device is limited to cutting approximately 12-inch diameter holes, which are insufficient in size to permit the passage of troops and large equipment.
Continuous Rod Warheads (CRWs) were originally designed for anti-aircraft operations. The design involved a warhead that, after being fired, radially projected an expanding bundle of zigzag connected rods at a relatively high velocity (e.g., 5,000 feet per second). The expanding bundle of rods would then impact the aircraft cutting and slashing through the aircraft structure. The MK82 Mod 0 warhead of the U.S. Navy AIM-54A Phoenix missile uses CRW technology. Additionally, the military has contemplated using CRW technology to clear terrain of foliage and structures (e.g., to clear a helicopter landing zone) by radially projecting a bundle of rods parallel to the ground, as described in U.S. Pat. No. 3,938,441.
CRW technology involves placing two concentric layers of rods around a cylindrical explosive charge. The alternating ends of the rods are connected together (e.g., by pinning or welding). When the explosive charge detonates, the rod layers are accelerated radially outward at a high velocity. The connections on alternating ends of the rods cause them to form a continuous “zigzag” pattern as they travel outward in an expanding circle or loop. As the rods continue to expand, a point is reached where the rods can no longer remain connected, and the zigzag circle breaks into sections. One problem with this technology is that the explosive charge does not expand the rods consistently in a smooth and even manner. Another problem with this technology is that the warhead requires a dedicated explosive charge for expanding the rods. This, in turn, can require special and/or additional handling and safety procedures.